Railway-traffic-controlling apparatus



INVENTOR r f Q,

H. A.. THOMPSON Filed Sept. 32, 1926 RAILWAY TRAFFIC CONTROLLING APPARATUS Feb. 21, 1928.

Patented Feb. 1,928. i r UNITED STATES nowaan A. masses, or nnenwoon uneven, rznnsirnvnm; sentence 'ro 51E UNION swIrcH a swan. comm, or swrsavann rnnnsrnvanu, A conrona- TION OF PENNSYLVANIA.

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Application as septeniber a 1923. serial no. 13 300.

My invention relates to railway trafl'ic controlling ap aratus, and particularly to apparatus of t c typecomprising tram carried governing means controlled by energy received from the trackway. More particularly my present invention relates to the trackway portion of such apparatus.

I will describe one form oftrackway appai-atus embodying my inventi will 10 then point out the novel features th f claims. A

Theaccompanying drawing s a diagram- .matic view illustrating one form of rallway traffic cortrolling apparatusembodying my invention. r a Referring to the drawing, the reference characters 1 and l designate the track rails of a stretch of railway track overwhlch trafiic at times moves in both directions. These track rails are divided, in

insulated joints 2, into a plura ity of successive track sections, AB, B'-G, etc. Each such track section isprovided with a track transformer designated the. reference character T with an ex onent corresponding to the location and aying asecondary 9 connected across the rails ad1acent the left-hand end of the corresponding section through a reactive impedance 5. The

3 primary 10 of each track transformer T is constantly supplied with alternating current, through the usual fuses 20 from a, suitable source, such as an alternatonM, over line Wires 3 and 3% Each track section is further provided with i a track relay, here designated by the reference character R withan exponent corresponding to the location and each comprising two WHldlIIgS and 5. Winding 5 of each relay Ris consection, and winding 4 of each relayB is constantly supplied with alternating current from line wires 3 and 3.

and described is suitable form-operation with train carried governing means not shown in the drawing in such manner that the governing means on the train is responsive to the presence or absence of alternating current in the rails of the section occupied by the train. The control of the train carried governing means by the trackway current is usually effected 1n such sysmeans of stantly connected across the rails adjacent The trackway apparatus herein shown trolling current mustbe connected with the rails at a point inadvance of the train. The

track transformers T can supply train controlling curent to trains moving from right to left. In order to supply train controlling v .currentto tra ns moving from left to right,

however, each section is further provided with an auxiliary transformer designated by the reference character K with anex ponent correspondingto the location and having a seconary 11 constantly connected across the rails adjacent the right-hand end of the corresponding section through a read tiveiinpedance 13. The primaryl2 of each transformer K is connected, through the usual fuses 21, with line wires 3 and 3 over a back contact 18 of the adjacent track rela R. In additionvto the control of thefprimary circuit for transformer K, each track relay may be utilizedito control governing means not shown in the drawing in any suitable manner. a

It is essential inosystems of the character described that thetrack relay should be deenergilzed when any 1, portion of the corre spondm section is occupied by a train. It

'is there ore importantjto arrange the apparatus in such manner that current from a transformer K can not energize the adja cent relay R. i This result is accomplished in the apparatus illustrated in the drawing in the following manner;

Referring particularl to section AB, a rectifier 7 is interpose between secondary 9 of transformer T and impedance 6, and a second rectifier 8 is connectedin parallel with secondary 9 and rectifier 7, the rectifiers 7 and 8 being so disposed that current is permitted to flow from secondary 9 only during thosehalf cycles of the current in which rail 1* is positive with respect to rail 1. Two

rectifiers 16 and 17 are connected in series former K and another rectifier 14: is connectedin parallel with rectifier l5 andscondary 11, the rectifiers 14: and 15 being so arranged that current can flow from secondary 11 to the track rails only during halfcycles of the opposite polarity'from that of the half cycles supplied to the trackway by transformer T. To state the matter in another way, transformer T supplies pulsating current to the rails of section A-B during the half cycles that rail 1 is positive with respect to rail 1, but when relay B is de-energized so that primary 12 of trans former K is energized, transformer K supplies energy tothe track rails during the half cycles that rail 1 is positivewith respect to mill. But current can flow through winding '5 of relay R only from rail 1 to rail 1. It will be seen, therefore, that the arrangement of the rectifiers is such that current from transformer K can not'fiow through winding 5 of relay R and it is therefore manifest that current from transformer K cannot interfere in any manner with the proper operation of this relay.

1n explaining the operation of the apparatusl will first assume that section A-B is occupied by a train so that relay B is deenergized and primary 12 of transformer K is supplied with alternating current, For. all practical purposes, the half-wave currents supplied to the rails by the trans formers T and K through the associated rectifiers are equivalent to full wave alternating currents. When a train occupies the section AB, if the train is moving from right to left, it will be supplied with train controlling current from transformer, T connected with the rails in advance of the train. If, however, the train is moving from left to right, it will be supplied with train controlling current bytransformer K connected with the rails in advance of the train.

When a train occupies section AB, current from transformer T is, of course, shunted away from relay R but winding '5 of this relay is connected directly in parallel with the primary of transformer K During the half cycles that current can flow from secondary-11 of transformer K to the rails the direction of the current is such that the rectifiers 16 and 17 prevent the flow of this current through the winding 5 of relay R But during eachsuch half cycle energy is stored in the impedance 13 and in the magnetic field surrounding the rails 1 and 1 During the succeeding half cycle the energy stored in the impedance 13 will tend to discharge current in the same direction as the direction of the current which'stored the energy but this current will also be'opposed by the rectifiers associated with relay R so that the energy stored in'the impedance 13 can not cause improper operation of relay R The energy stored in the track rails during the half cycle that transformer K is supplying current to the track rails tends the half cycles that transformer K is supplying energy to the traclr rails 1 make the impedance 13 comparatively large with respect to the impedance of the track rails so i that at'all times the energy stored in this impedance is greater than the energy stored in the track rails, with the result that during the half cycles that transformer K is not feeding current to the track rails, the discharge from impedance 13 will overbalance the discharge from the rail impedance and will prevent operation of the relay.

lVhen the train passes out of sect-ion'A-B, current from transformer T is permitted to flow throughwinding 5 of relay R and causes this relay to become energized. The consequent opening of back contact 18 of the relay interrupts the primary circuit for transformer K and discontinues the supply of alternating current to therails from this 7 transformer. Under these conditions current from transformer T flows through winding 5 of relay R but in parallel with this relay there are two other paths for such current, one through rectifier 14- and impedance 13 and the other through winding 11 of transformer K rectifier 15 and impedance 13. As long as the impedance of 13 is comparatively high, current through the first path will be comparatively small and the current through the second path will be still smaller due to the additional impedance of the secondary 11. During the brief interval immediately following the departure of the train from the track section, primary 1270f transformer K is energized and during this brief interval the current in the second path just traced is still further reduced by the electromotive force of transformer K this el'ectromotive force being opposed to the electromotive force which causes the current which energizes relay R The shunting effect of these two paths is therefore negligible, and does not interfere with the operation of relay R by current from transformer T 7 p Should rectifier 15 become short circuited both halves of the wave from transformer K would pass the rectifier and current of thepolarity normally suppressed by rectifier 15 might falsely energize relay R Current of this polarity would be shunted by rectifier 1 1- however, and this shunting effect would blow out one or both of the fuses 21 inserted in circuit with primary 12 of transformer K A short circuit in one of the rectifiers 15 therefore can not operate an adjacent relay R.

Furthermore should rectifier 16 associated with relay R for example, become short ciremme cuited, current of the polarity normally sup} be connected with the two ends, respectively of a tracl section and that a track relay also connected with the rails of the section will respond to current from one of the sources connected with that section andwill be immune to the effects of current supplied from the other source. i

Although I have herein shown and describedonly one format trackway apparatus embodying my invention it is understood that various changes and modifications may be made therein within the scope of the appended claims Without departing from the spirit and scope of my invention. i

Having thus described my inventiomwhat I claim is: V a i i 1. In combination, a pair of conductors, two sources of alternating current connected in parallel with said conductors, an electro responsive device having -a winding connected with said conductors, and rectifiers interposed between each said-source and a conductor and between said winding and a conductor .for permitting current from one source but not current from the other source to flow through said winding.

2. In combination, a stretch of railway track, two sources of alternating current connected across the rails adjacent the two ends of the stretch respectively, a track relay having a winding connected across the track rails, and rectifiers connected between each source and a rail. and between said winding and a rail for permitting current from one source butnot current from the other source to flow through said winding.

3. In combination, a stretch of railway track, a source of alternating current connected across the rails of the stretch, a track relay having a winding connected with the rails and responsive to current from said source, a second source of alternating current connected across the rails of the stretch, and rectifiers interposed between said winding and a rail and between said second source and a rail for preventing the flow of current from said second source through said winding. i

i. In combination, a stretch of railway track, two sources of alternating current connected across the rails of the stretch, rectifiers interposed between each said'source and a rail of the section for permitting the flow of current to the rails from one source only during half cycles of one polarity and fromthe other source only during half cycles of theopposite polarity, a track relay having a winding connected with the rails, and a rectifier interposed between said winding and arail for preventing the how of current from the rails through the relay during half cycles of onepolarity. i a

5. In combination, a stretchof railway track, two sources of alternating current connected across the lttl'lS of sa1dstretch,

two series rectifiers one interposed between each transformer anda rail in suchmanner that the sources supply current to the rails during hall cycles of opposite polarity two other rectifiers one connected in parallel with each source and .the'series rectifier assoei ated therewith and offering its higher resistanceto current flowing from such source through the seriesrectifier in its low resistance direction, a track relay having a winding connected with the rails, a fifth rectifier connected in series with said winding for preventing the flow of current of one .polarity through said windings, and a sixth rec tifier connected in parallel with said winding and offering its higher resistance tocurrent flowing through said fifth rectifier. V

6. In combination, a stretch of railway track, two sources of alternating current connected with the rails of the stretch, two reactive impedances, one interposed between each source and a rail of the: stretch two rectifiers one interposed between each source and the associated impedance in such manner that the sources supply current. to the rails only during half cycles of opposite polarity, two other rectifiers, one connected .1n parallel with each source and the associated rectifier, a track relay having a winding connected across the rails of the stretch, and two other rectifiers one connected in series and the other in parallel with said Winding and arranged to offer their higher resistances to currents of opposite polarities.

7. In combination, a stretch of railway track, two sources of alternating current connected with the rails adjacent opposite ends of the stretch, a comparatively small reactive impedance interposed between one source and a rail of the stretch, a rectifier interposedbetween such impedance and the associated source for 7 ermitting the flow of ourrent onl during alf cycles of one polarity, a secon rectifier connected in parallel with said one source and the first rectifier and offering its higher resistance to current of such one polarlty, a comparatively large reactive impedance interposed between the other source and a, rail, :1. third rectifier interposed between such impedance and the associated source for permitting the flow of current only during half cycles of the opposite polarity, a fourth rectifier connected 1n parallel with such other source and said third rectifier and offering its higher resistance to current of such opposite polarity,

a track relay having a winding connected with the rails adjacent the point of connection of such other source, a fifth rectifier connected in series with said winding for permitting current of said one polarity only to flow through the winding, and a sixth rectifier connected in parallel with said winding and ofiering its higher resistance to current or" such one polarity.

8. In combination, a pair of conductors,

an electro-responsive device having a winding connected with the conductors, a source ofcurrent of one-polarity connected with the conductors, a source of alternating current connected with the conductors, and rectifiers interposed between said source of alternating current and one conductor and between the winding and a. conductor for permitting current from the first source but not current .from the source of alternating current to the winding for shunting current away from the winding should one of the first mentioned rectifiers become short circuited.

10. In combination, a pair of conductors, an electro-responsive device having a winding connected with the conductor-s, a source of alternating current connected with the conductors, a first rectifier connected in series with the source, a second rectifier connected in series'with the winding, said first and second rectifiers operating to prevent current from the source from flowing through the winding, and a third rectifier connected in parallel with the winding to shunt current away from the wii'iding should the second rectifiers become short circuited.

11. In combination, a pair of conductors, an electro-rcsponsive device having a winding connected with the conductors, a source of alternating current connected with the conductors, a first rectifier connected 1n series with the source, a second rectifier con-' nected in series with the winding, said first and second rectifiers operating to prevent current from the source from flowing through the winding, and a third rectifier connected in parallel with the source to shunt current away from the winding should the first rectifier become short circuited.

In testimony whereof I alfix my signature.

HOWARD A. THOMPSON. 

